For months, Mr. Netanyahu has been calling on the US to specify a point in Iran's nuclear development that, if crossed, would trigger military intervention. The US has steadfastly refused to commit itself to a specific point, prompting the Israeli leader to take his case to the international community.

While his presentation certainly got attention, some experts say that Netanyahu’s prop missed the mark, confusing where his red line lies rather than simplifying the issue. The problem, they said, is that his presentation conflated two different types of numbers.

The bomb chart showed percentage progress toward acquiring enough fissile material to make a bomb. Netanyahu said the Iranians were 70 percent of the way there and drew his now famous red line at the 90-percent threshold, a milestone he predicted would be reached sometimes next spring or summer.